Deploying large numbers of small, low-power cores has been gaining traction recently as a system design strategy in highperformancecomputing (HPC). The ARM platform that dominates the embedded and mobile computings...
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The u.s. Department of Defense highperformancecomputingmodernizationprogram (HPCMP) has implemented sustained systemsperformance testing on highperformancecomputingsystems in use at dodsupercomputing Resource...
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ISBN:
(纸本)9781450311397
The u.s. Department of Defense highperformancecomputingmodernizationprogram (HPCMP) has implemented sustained systemsperformance testing on highperformancecomputingsystems in use at dodsupercomputing Resource Centers. The intent is to monitor performance improvements by updates to the operating system, compiler suites, and numerical and communications libraries, and to monitor penalties arising from security patches. In practice, each system's workload issimulated by appropriate choices of user application codes representative of the HPCMP computational technical areas. Past successes include surfacing an imminent failure of an OsT in a Cray XT3, incomplete configuration of a scheduler update on an sGI Altix 4700, performance issu.s.associated with a communications library update for a Linux Networx Advanced Technology Cluster, and intermittent resetting of Intel Nehalem cores to standard mode from turbo mode. This history demonstrates that ssP testing is critical to deliver the highest quality of service to the HPCMP users. Copyright 2011 ACM.
Lattice Boltzmann algorihms are a mesoscopic representation of nonlinear continuum physics (like Navier-stokes, magnetohydro dynamics (MHD), Gross- Pitaevskii equations) which are ideal for parallel supercomputers bec...
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Lattice Boltzmann algorihms are a mesoscopic representation of nonlinear continuum physics (like Navier-stokes, magnetohydro dynamics (MHD), Gross- Pitaevskii equations) which are ideal for parallel supercomputers because they transform the difficult nonlinear convective macroscopic derivatives into purely local moments of distribution functions. The macroscopic nonlinearities are recovered by relaxation distribution functions in the collision operator whose dependence on the macroscopic velocity is algebraically nonlinear and thus purely local. unlike standard computational fluid dynamics codes, there is no loss in parallelization in handling arbitrary geometric boundaries, e.g., using bounce-back rules from kinetic theory. By encoding detailed balance into the collision operator through the introduction of discrete H-function, the lattice Boltzmann algorithm can be made unconditionally stable for arbitrary high Reynolds numbers. It isshown that this approach is a special case of a quantum lattice Boltzmann algorithm that entangles local qubits through unitary collision operators and which is ideally parallelized on quantum computer architectures. Here we consider turbulence simulationsusing 2,048 PEs on a 1,6003-spatial grid. A connection is found between the rate of change of enstrophy and the onset of laminar-to- turbulent flows.
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